VERIFIED(Source-Verified)

420 Stainless Steel

Primary Designation:TYPE 420

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Data Completeness:6 composition elements and 12 condition-specific property values cataloged.

Omitted fields represent unverified properties. "Missing is better than invented."

Key Engineering Properties

Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.

Density

7.75 g/cm³TYPICAL · temperature not stated

Thermal Conductivity

24.9 W/(m·K)TYPICAL · at 100 °C

Composition Excerpt

C > 0.15 wt%Carbon (min)

Standard Elemental Basis: MIN

Tensile Strength

≥ 585 MPaMINIMUM · Annealed · temperature not stated

Engineering Summary

420 Stainless Steel. Source-scoped engineering data is shown with its reported limits and conditions. Unreported properties are not inferred.

Recognized Aliases

Source-backed commercial trade name and short designations cataloged in canonical data.

420 Stainless Steel Specifications & Designations

Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.

Direct Standard DesignationsDIRECT DESIGNATION

1 Primary Identifier

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System	Identifier	Standard System Name	Classification Notes & Provenance
TYPEPRIMARY	420	Producer-referenced stainless type	—Ref: Practical Data for Metallurgists, 19th edition

Applicable Specifications & Product Form ReferencesSPECIFICATION REFERENCE

1 Applicable Standards

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Standards Body	Specification Code	Specification Title / Scope	Relationship Type
420	420 Stainless Steel Engineering Datasheet	Applicable specification reference.	Specification Reference

Engineering Notice: Applicable specifications establish manufacturing requirements, dimensional tolerances, and test criteria for specific product forms (e.g. bus bar, wire, plate, pipe). They represent applicable technical standards, not alternative or equivalent alloy grades.

420 Stainless Steel Chemical Composition

Chemical Composition (Weight %) — Elemental limits and values from the cited source. Preserves exact semantic limits (minimums, maximums, and ranges).

Scroll horizontally for full elemental limits

Element	Symbol	Atomic No.	Semantic Basis	Specified Value	Unit	Metallurgical Notes & Qualification	Data Status
Carbon	C	6	MINIMUM	> 0.15	wt%	Source cell: >.15. Scope: p24, Type 420.Ref: Metallus	VERIFIED
Manganese	Mn	25	MAXIMUM	≤ 1.00	wt%	Source cell: 1.00max. Scope: p24, Type 420.Ref: Metallus	VERIFIED
Silicon	Si	14	MAXIMUM	≤ 1.00	wt%	Source cell: 1.00max. Scope: p24, Type 420.Ref: Metallus	VERIFIED
Phosphorus	P	15	MAXIMUM	≤ 0.04	wt%	Source cell: .040max. Scope: p24, Type 420.Ref: Metallus	VERIFIED
Sulfur	S	16	MAXIMUM	≤ 0.03	wt%	Source cell: .030max. Scope: p24, Type 420.Ref: Metallus	VERIFIED
Chromium	Cr	24	RANGE	12.00 – 14.00	wt%	Source cell: 12.00/14.00. Scope: p24, Type 420.Ref: Metallus	VERIFIED

* Elemental percentages are expressed in weight percent (wt%). Values represent applicable specification limits. Unspecified trace elements are not fabricated or assumed.Preserves exact semantic basis

Property Display UnitsSwitch between Canonical SI and Source / US Customary units:

420 Stainless Steel Physical Properties

Source-specific physical properties. Test temperatures are shown only where reported.

3 Parameters

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Property Parameter	Canonical SI Value	Semantic Basis	Source Raw Reference	Source Reference	Status
Density	7.75 g/cm³	TYPICAL	7.75 g/cm3	ATI (Allegheny Technologies Incorporated)	VERIFIED
Elastic Modulus	200 GPa	TYPICAL	200 GPa	ATI (Allegheny Technologies Incorporated)	VERIFIED
Poisson's Ratio	0.28 dimensionless	TYPICAL	0.28 dimensionless	ATI (Allegheny Technologies Incorporated)	VERIFIED

420 Stainless Steel Thermal & Thermodynamic Properties

Phase change temperatures, thermal conductivity, specific heat, mean coefficients of thermal expansion across standardized temperature ranges, and recommended thermal processing windows.

2 Parameters

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Property Parameter	Canonical SI Value	Semantic Basis	Test Temperature / Context Range	Source Raw Reference	Source Reference	Status
Coefficient of Thermal Expansion	10.5 µm/(m·K)	TYPICAL	Test Temp: 100 °C	10.5 10^-6/K	ATI (Allegheny Technologies Incorporated)	VERIFIED
Thermal Conductivity	24.9 W/(m·K)	TYPICAL	Test Temp: 100 °C	24.9 W/(m·K)	ATI (Allegheny Technologies Incorporated)	VERIFIED

420 Stainless Steel Electrical Properties

Electrical conductivity and resistivity in their reported units and conditions.

1 Parameters

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Property Parameter	Canonical SI Value	Semantic Basis	Test Temperature / Context Range	Source Raw Reference	Source Reference	Status
Electrical Resistivity	550 nΩ·m	TYPICAL		55 µΩ·cm	ATI (Allegheny Technologies Incorporated)	VERIFIED

420 Stainless Steel Mechanical Properties

Contextual Mechanical Properties & Tempers: Engineering strength, ductility, and hardness values grouped by product form, temper, and section thickness. Mechanical properties are contextual and not isotropic averages.

Temper / Condition:

Showing 5 of 5 conditions

Scroll horizontally for all conditions & tempers

Product Form	Temper / Condition	Section Size	Tensile (UTS)	Yield Strength	Elongation	Shear Strength	Fatigue Strength	Hardness (Scales Preserved)	Status
Bar and Strip	Annealed · Annealed Source values and qualifiers Ultimate Tensile Strength: ≥ 585 MPa (MINIMUM)ASTM A276ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Mechanical Properties Table	—	≥ 585 MPa	—	—	—	—	—	VERIFIED
Bar and Strip	Annealed · Annealed Source values and qualifiers Yield Strength: ≥ 345 MPa (MINIMUM)ASTM A276 (0.2% offset)ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Mechanical Properties Table	—	—	≥ 345 MPa	—	—	—	—	VERIFIED
Bar and Strip	Annealed · Annealed Source values and qualifiers Elongation at Break: ≥ 15 % (MINIMUM)ASTM A276ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Mechanical Properties Table	— · in 50 mm (2 in)	—	—	≥ 15 %	—	—	—	VERIFIED
Bar and Strip	Hardened and Tempered (200°C temper) · Oil quenched 1010°C, tempered 200°C Source values and qualifiers Ultimate Tensile Strength: 1720 MPa (TYPICAL)ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Heat Treated Properties Table HRC Hardness: ≥ 50 HRC (MINIMUM)ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Heat Treated Properties Table	—	1720 MPa	—	—	—	—	≥ 50 HRC	VERIFIED
Bar and Strip	Annealed Source values and qualifiers HB Hardness: ≤ 241 HB (MAXIMUM)ATI (Allegheny Technologies Incorporated) — ATI 420 Datasheet, Mechanical Properties Table	—	—	—	—	—	—	≤ 241 HB	VERIFIED

Hardness Integrity Notice: Rockwell B (HRB), Rockwell F (HRF), and Superficial 30T (HR30T) scales are reported on their measured scales without cross-scale mathematical conversion.

Source: See fact-level citations

Practical Engineering & Fabrication Notes

By Mat Grades Editorial Desk · Updated 2026-11-14. Use alongside the specified product standard and supplier certificate.

Machining & shop-floor behavior

For 420 Stainless Steel, a qualified cutting-speed or tool-life recommendation is not supplied in the available record. A relevant hardness example is HB Hardness: maximum 241 HB (maximum; Annealed, Bar and Strip). Use that supplied condition for a trial of the difficult feature. Record tool changes, burr removal, unclamped dimensions and accepted parts per hour. Relative machinability ratings from different reference scales should not be compared as if they were one common test.

Weldability, brazing & joining

No qualified weld procedure, filler selection or preheat/interpass schedule is established by this material record. Obtain a procedure for the actual joint, supplied condition and section rather than copying one from a nearby grade. The first cataloged strength example is Ultimate Tensile Strength: minimum 585 MPa (minimum; Annealed, Bar and Strip). Assess the final part after joining or thermal processing. Include distortion, cleanup and inspection in the quotation. A material designation or favorable process rating is a starting point for qualification, not evidence that an untested joint meets the drawing.

Corrosion & service environment

Assess chlorides, deposits, crevices, temperature and the final cleaned surface together. Stainless is not a promise of immunity to corrosion. Check weld heat tint and embedded iron where fabrication is involved, and do not turn a thermal-property test temperature into a service ceiling. The recorded thermal example is Coefficient of Thermal Expansion: 10.5 µm/(m·K) (typical; ; test temperature 100 °C). State the exposure and inspection access in the design record so that a change of installation or cleaning method triggers a review. The selected composition entries are C minimum 0.15 wt%, Mn maximum 1 wt%, Si maximum 1 wt%. Chemistry documents identity; it does not establish fluid compatibility.

Selection trade-offs & applications

Use TYPE 420, SPECIFICATION 420 Stainless Steel Engineering Datasheet to identify the candidate, then specify the product form and delivered condition separately. A specific component application is not asserted where the source record does not provide one. The listed forms include Bar and Strip; confirm the actual stock offered by the supplier. Compare the complete route through machining, joining, finish and inspection. Keep the certificate, required test location and acceptance criteria with the first-article record. A later change of grade, condition or source should be assessed against that same requirement.

Technical references: ATI (Allegheny Technologies Incorporated); Metallus

Martensitic Steel Alloy Family

Corrosion-resistant stainless steels in the Martensitic metallurgical branch sharing equivalent matrix structures.

3 Adjacent Grades

S41600C: ≤0.15%

Type 416 Stainless Steel

View Grade →

410C: ≤0.15%

410 Stainless Steel

View Grade →

420Current Grade

420 Stainless Steel

Related Engineering & Metallurgy Guides

Contextual technical guides explaining degradation mechanisms, testing methodologies, and selection criteria relevant to 420 Stainless Steel.

Corrosion & Surface Engineering16 min read

How to Polish Stainless Steel: Methods, Scratch Removal, Finishes & Grain Direction

Stainless steel owes its corrosion resistance to a microscopic, self-healing chromium oxide (Cr₂O₃) passive film. Polishing stainless steel is not merely cosmetic cleaning—it is a controlled mechanical abrasion process requiring strict adherence to grain direction, progressive abrasive refinement, and rigorous cross-contamination control to preserve surface integrity and corrosion performance.

Author: Mat Grades Editorial DeskRead Guide →

Sources

Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.

MetallusPractical Data for Metallurgists, 19th edition

PRIMARY PRODUCER

Reviewed factual transcription; source document SHA-256 is recorded in the capture metadata. No cross-standard equivalence is asserted.

Issuing Body: MetallusRevision: 19th edition, 2024View Source Record ↗

ATI (Allegheny Technologies Incorporated)ATI Technical Data Sheets: Stainless Steel Engineering Specifications

PRIMARY PRODUCER

Reviewed factual transcription from primary producer engineering datasheet.